194,737 research outputs found
Chaos in the Outer Solar System
We study the effect of a perturber on the energy and angular momentum of a test particle on a highly eccentric orbit. We find that both the energy and angular momentum of the test particle are adiabatic invariants when the perturber is on a circular orbit with radius much smaller than the periaps of the test particle. We derive analytical expression for the energy change, or kick, of the test particle with every periaps passage. Using this kick function we formulate mapping for the highly eccentric test particle. We also analyze the stability of resonances and find conditions for asymmetric libration to occur. The resonance widths for highly eccentric orbits are calculated and the criterion for the onset of global chaos is determined
Planet Formation in the Outer Solar System
This paper reviews coagulation models for planet formation in the Kuiper
Belt, emphasizing links to recent observations of our and other solar systems.
At heliocentric distances of 35-50 AU, single annulus and multiannulus
planetesimal accretion calculations produce several 1000 km or larger planets
and many 50-500 km objects on timescales of 10-30 Myr in a Minimum Mass Solar
Nebula. Planets form more rapidly in more massive nebulae. All models yield two
power law cumulative size distributions, N_C propto r^{-q} with q = 3.0-3.5 for
radii larger than 10 km and N_C propto r^{-2.5} for radii less than 1 km. These
size distributions are consistent with observations of Kuiper Belt objects
acquired during the past decade. Once large objects form at 35-50 AU,
gravitational stirring leads to a collisional cascade where 0.1-10 km objects
are ground to dust. The collisional cascade removes 80% to 90% of the initial
mass in the nebula in roughly 1 Gyr. This dust production rate is comparable to
rates inferred for alpha Lyr, beta Pic, and other extrasolar debris disk
systems.Comment: invited review for PASP, March 2002. 33 pages of text and 12 figure
Dust Measurements in the Outer Solar System
Dust measurements in the outer solar system are reviewed. Only the plasma
wave instrument on board Voyagers 1 and 2 recorded impacts in the
Edgeworth-Kuiper belt (EKB). Pioneers 10 and 11 measured a constant dust flux
of 10-micron-sized particles out to 20 AU. Dust detectors on board Ulysses and
Galileo uniquely identified micron-sized interstellar grains passing through
the planetary system. Impacts of interstellar dust grains onto big EKB objects
generate at least about a ton per second of micron-sized secondaries that are
dispersed by Poynting-Robertson effect and Lorentz force. We conclude that
impacts of interstellar particles are also responsible for the loss of dust
grains at the inner edge of the EKB. While new dust measurements in the EKB are
in an early planning stage, several missions (Cassini and STARDUST) are en
route to analyze interstellar dust in much more detail.Comment: 10 pages, 5 figures, Proceedings of the ESO workshop on ``Minor
bodies in the outer solar system'
Shock wave propagation in porous ice
We present data on shock wave propagation in porous ice under conditions applicable to the outer solar system. The equation of state of porous ice under low temperature and low pressure conditions agrees well with measurements under terrestrial conditions implying that data on terrestrial snow may be applicable to the outer solar system. We also observe rarefaction waves from small regions of increased porosity and calculate release wave velocities
Outward to the Beginning: the CRAF and Cassini Missions of the Mariner Mark 2 Program
Two successive journeys will soon offer a perspective on the origin of the solar system and perhaps provide clues on the origin of life as well. The missions, the Comet Rendezvous Asteroid Flyby (CRAF) and Cassini (the Saturn orbiter/Titan probe), combine to form the first initiative of the Mariner Mark 2 program, a series of planetary missions whose common objective is to explore primitive bodies and the outer solar system, toward the ultimate goal of understanding the nature of our origins. Cassini and CRAF are exciting planetary missions. The objectives that they share, the region of the solar system in which comets, asteroids, and the Saturnian system have evolved and now reside, and the spacecraft that will carry both sets of experiments to their targets in the outer solar system are described
Studies of relationships among outer solar system small bodies and related objects
This program involves telescopic observations of colorimetry, spectroscopy, and photometry of small bodies of the solar system, emphasizing possible relationships among outer solar system asteroids, comets, and certain satellites. Earth approacher targets of opportunity and lab spectroscopic studies are included
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